Fenders for boats are known consisting of a half-round in stainless steel, formed from rolled strip, countersunk and pierced with a blanking tool, laid over a PVC base which has the task of cushioning and protecting the gel coat (polyester resin-based substance used to coat fibreglass to make it impervious) of the boat from the metal.
The advantages of this solution are the very low weight and cost, while the disadvantages are the result of the impossibility of bending the half-round manually over the perimeter of the boat because it yields and deforms (torsion) in the area of the fixing holes.
Applying this type of fender necessarily requires radial bending with costly equipment. Furthermore it is necessary to make profiles to measure, i.e. varying according to the type of curve and type of boat.
Finally, a profile made in accordance with this solution is fairly vulnerable to impact.
A second solution is also known which provides for a half-round (therefore solid) section in drilled steel obtained by forging and rolling, with various heat treatments, therefore forging and countersinking with a drill, besides final polishing.
Said solution entails very high costs and substantial weight above the boat's centre of gravity; it is easier to fit manually but there remains the risk that it will give way at the drilling points (because of the weight).